Process for the production of knop yarns and apparatus therefor



Feb. 6, 1962 STIEFFENHOFER 3,020,173 PROCESS FOR THE PRODUCTION OF KNOPYARNS AND APPARATUS THEREFOR Filed May 13, 1958 INVENTOR A 00/; 57/EFFE/VHO F767? ATTORNEY 3 e20 173 rnocnss non Tim rabnnc'rroN F KNOPYARNS AND APPARATUS THEREFOR Louis Stieifenhofer, Chavanoz, France,assignor to States Patent 0 This invention relates to knop yarns hereindefined as yarns having at more or less regular intervals protuberancesadhering in the form of small beads.

The basic fiber may be a natural fiber or an artificial or syntheticfilament, with or without a core, which may consist of a natural,artificial or synthetic spun yarn, or may be based on glass, metal, etc.

In a known process, improved filaments are obtained by coating anappropriate core, for example consisting of spun glass fiber, with apolyvinylchloride plastisol, which may contain in addition loadingagents, pigments, ancillary products, etc., as the fiber passes througha a spinneret, drying the coated fiber and subjecting it to anappropriate thermal treatment with transformation of the layer ofplastisol into a coating solidly adhering to the core yarn. Theplastisol employed has very high viscosity.

It has been found that small beads can be produced on the products thusobtaining by recoating with dilute plastisol a spun yarn coated in themanner described, notably by means of an appropriate device whichconsists of a nozzle formed of a cone having a fine axial hole extendingthrough the tip, the said nozzle being fed with an excess of liquidwhich can escape through a large lateral hole in the cone.

The invention will be more readily understood from the accompanyingdrawing in which the figure is a diagrammatic illustration of a formingsystem embodying the invention.

Example A spun glass yarn No. 45 is coated with a polyvinylchlorideplastisol in two phases, with drying and thermal treatment after eachphase. The plastisol has very high viscosity.

The coated yarn F is then dipped into a dilute plastisol having lowviscosity. The yarn coated with dilute plastisol thereafter passeshorizontally into a nozzle as illustrated in the drawing. This nozzlecomprises a hollow cylindrical body 1 extended by a cone 2 formed withan axial hole 3 only slightly larger than the yarn, for example of 0.30mm. Situated below the axial hole 3 is a discharge hole 4 for the excessof coating solution which may be recovered and reused. This dischargehole is several times larger than the hole in the nozzle, for example 10times as large.

On leaving the nozzle opening 3, the coated yarn remains smooth. Theintroduction of the yarn into the oven 5 for the thermal treatment athigh temperature (more than 200 C.) comprising a bank of infra-redradiation lamps 6, produces a contraction of the coating,

3,826,173 Patented Feb. 6, i962 ice 2 which is still fluid, and theformation of small regular beads.

It is obvious that the example described does not in any way limit thescope of the invention.

The dilute plastisol may be of the same color as the basic coating, butvery attractive effects are obtained when the base and the beads are ofditferent colors, and especially if they are of contrasting colors.

By varying the viscosity of the dilute plastisol, the size of the beadsand/or the distance between them can be varied. More or less irregularlydistributed beads may be obtained by using baths mixed in variableproportions.

It is not essential for the artificial resin constituting the essentialingredient of the basic coating to be the same as that of the beads, butif the two resins are the same an excellent adhesion of the beads isobtained. Otherwise, anchoring means may be provided.

The example describes the production of the knop yarn by a new treatmentof a coated spun yarn already finished in a separate operation. However,the new treatment may also be directly applied to the process ofmanufacture of a coated spun yarn.

What is claimed is:

1. A process for the manufacture of knop yarns which comprises applyingto a yarn having a first coating layer of a plastisol thereon, anadditional coating layer consisting of a second plastisol of lowviscosity capable of adhering to said first coating layer and ofshrinking when dried, passing said coated yarn through a nozzle having arestricted opening adapted to remove the excess of said low viscosityplastisol, and passing said yarn through a drying zone to dry said lowviscosity plastisol and to cause the latter to shrink and form spacedbeads on said yarn.

2. The method set forth in claim 1 wherein the first plastisol is a highviscosity solution of the same material as the low viscosity plastisol.

3. Apparatus for producing knop yarns comprising a cylindrical nozzlehaving a horizontal axis, with a conical head formed with an openingonly slightly larger than the basic yarn, the said opening extendingaxially through the tip of the conical head, said head having inaddition a liquid discharge opening substantially larger than the nozzleopening and situated below the latter in the conical head, and a dryingoven disposed to receive the coated yarn from said nozzle.

References Cited in the file of this patent UNITED STATES PATENTS1,179,946 Lewis Apr. 18, 1916 1,776,073 Girard et a1 Sept. 16, 19301,777,096 Chapelle Sept. 30, 1930 2,293,379 Bruining Aug. 18, 19422,354,110 Ford et al. July 18, 1944 2,357,168 Bruining Aug. 29, 19442,407,337 Kolter Sept. 10, 1946 2,428,716 McGill et al Oct. 7, 19472,647,296 Shive Aug. 4, 1953 2,718,476 Eichorn Sept. 20, 1955 2,910,383Miller et a1 Oct. 27, 1959

1. A PROCESS FOR THE MANUFACTURING OF KNOP YARNS WHICH COMPRISESAPPLYING TO THE YARN HAVING A FIRST COATING LAYER OF A PLASTISOLTHEREON,AN ADDITIONAL COATING LAYER CONSIATING OF A SECOND PLASTISOL OFLOW VISCOSITY CAPABLE OF ADHERING TO SAID FIRST COATONG LAYER AND OFSHRIKING WHEN DRIED, PASSING SAID COATED YARN THROUGH A NOZZLE HAVING ARESTRICTED OPENING ADAPTED TO REMOVE THE EXCESS OF SAID LOW VISOCOSITYPLASTISOL, AND PASSING SAID YARN THROUGH A DRYING ZONE TO DRY SAID LOWVISCOSITY PLASTISOL AND TO CAUSE THE LATTER TO SHINK AND FORM SPACEDNEADS ON SAID YARN.